1. Field of the Invention
The present invention relates to a photoresist composition and a method of manufacturing a thin-film transistor substrate using the photoresist composition. More particularly, the present invention relates to a photoresist composition capable of being used for a four-mask process and a method of manufacturing a thin-film transistor substrate using the photoresist composition.
2. Description of the Related Art
A liquid crystal display (LCD) apparatus displays an image using optical and electrical properties of liquid crystal, such as an anisotropic refractive index and an anisotropic dielectric constant. The LCD apparatus has characteristics such as lighter weight, lower power consumption, lower driving voltage, etc., in comparison with other types of display apparatuses, such as a cathode ray tube (CRT), a plasma display panel (PDP) and so on.
Generally, the LCD apparatus includes an LCD panel and a light source providing the LCD panel with light. The LCD panel includes a plurality of pixels and a plurality of thin-film transistors (TFTs). The pixels and the TFTs are formed through a photolithography process using a photoresist composition. Recently, a four-mask process using four masks for forming the TFTs has been developed so as to simplify processes for forming the TFTs.
In the four-mask process, a photoresist pattern formed on a data metal layer includes a channel portion having a relatively small thickness. A conventional photoresist composition has relatively low heat resistance so that the channel portion of the photoresist pattern is deformed in the course of baking the photoresist pattern. In order to solve the above-mentioned problems, a photoresist composition having relatively high heat resistance has been developed. However, the adhesion ability between a photoresist pattern formed using the photoresist composition and a substrate on which the photoresist pattern is formed may be deteriorated.